Hubbell GFCI Sensing Module Catalog Page

Ground Fault Products

GFCI Sensing Module, 50A Maximum Rating - NEMA 4X

Typical Applications Include:

Power Generators, Spas, High Pressure Washers, Power Centers, Refineries and Mobile Power.

The sensing module functions interdependently with a magnetic branch circuit breaker. The module monitors
the electrical circuit by use of an external differential current transformer. No direct load is present at the module.
In the event of a ground fault, the load is interrupted by way of the hydraulic magnetic circuit breaker utilizing a
shunt trip coil.

This line of Sensing Modules is rated from 1 to 50 Amps and circuit current-carrying conductors from 1 to 3 poles.
Product is available with an automatic or manual “safe start” reset feature. The enclosure, when mounted with

the supplied gasket, achieves a UL NEMA 4X Rating.
This module and breaker system is ideal for portable generator integration protecting all outlets on a generator.
This system meets the proposed requirements for generators Underwriters Laboratory Standard 2201.
UL/cUL 943 Listed, Class A 4-6mA trip level and UL 1053 Compliant.

GFCI Sensing Module – 50A Maximum

Description Catalog Number

120V AC Sensing Module Auto GFS M120A
120V AC Sensing Module Manual GFS M120M
240V AC Sensing Module Auto GFSM240A
240V AC Sensing Module Manual GFSM240M

GFSM120M

GFSMCB120401P

Wiring Schematics

Current carrying leads must
be twisted as they go through
the sensing module.

PART #
AUTO GFSM120A
MAUUAL GFSM120M

H
N

120V AC
IN

SINGLE PHASE 120VAC (HOT, NEUTRAL, GRND)

GROUND

GFCI Sensing Module, 50A Maximum Rating - NEMA 4X Ground Fault Products

120VAC GFCI
SENSING
MODULE

GFCI Sensing Module Circuit Breakers

Catalog Number Configurator -
Example Catalog Number: GFSMCB120401P

GFSMCB 120 40 1P
Ground Fault

Sensing Module
Circuit Breaker

120 Volt

240 Volt
120/240 Volt

OtherExamples:

GFSMCB240502P: 240V 50A 2P
GFSMCB240203P: 240V 20A 3P

GFSMCB120XX1P

CIRCUIT
BREAKER

LOAD

NO
C

LINE

WHITE
BLACK
YELLOW (SHUNT)

ORANGE
SHUNT
JUMPER

LOAD--->

Current carrying leads must
be twisted as they go through
the sensing module.

H

L1

N

L2

240V AC
IN

SINGLE PHASE 240VAC (L1, L2, GRND)

G

GROUND

PART #
AUTO GFSM240A
MAUUAL GFSM240M

240VAC GFCI
SENSING
MODULE

1 thru 50
Amp

GFSMCB240XX2P

CIRCUIT
BREAKER

LOAD

LINE

RED
BLACK
YELLOW (SHUNT)

1P

2P
3P

GFSMCB120XX2P

ORANGE
SHUNT
JUMPER

NO
C

LOAD--->

Current carrying leads must
be twisted as they go through
the sensing module.

L1

L2

L2
L1

N
120/
240 V AC
IN

G

GROUND

PART #
AUTO GFSM120A
MAUUAL GFSM120M

120VAC GFCI
SENSING
MODULE

SPLIT PHASE 120/240VAC (L1, L2, N, GRND)

LOAD

LINE

CIRCUIT
BREAKER

NO
C

WHITE
BLACK
YELLOW (SHUNT)

ORANGE
SHUNT
JUMPER

LOAD--->

L2

L1

N

G

H-10 Dimensions in Inches (mm)